src/HOL/UNITY/UNITY.ML
author paulson
Wed Sep 01 11:16:02 1999 +0200 (1999-09-01)
changeset 7403 c318acb88251
parent 7345 59bc887290df
child 7594 8a188ef6545e
permissions -rw-r--r--
tidied some proofs
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(*  Title:      HOL/UNITY/UNITY
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    ID:         $Id$
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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    Copyright   1998  University of Cambridge
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The basic UNITY theory (revised version, based upon the "co" operator)
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From Misra, "A Logic for Concurrent Programming", 1994
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*)
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set proof_timing;
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(*** General lemmas ***)
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Goal "UNIV Times UNIV = UNIV";
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by Auto_tac;
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qed "UNIV_Times_UNIV"; 
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Addsimps [UNIV_Times_UNIV];
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Goal "- (UNIV Times A) = UNIV Times (-A)";
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by Auto_tac;
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qed "Compl_Times_UNIV1"; 
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Goal "- (A Times UNIV) = (-A) Times UNIV";
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by Auto_tac;
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qed "Compl_Times_UNIV2"; 
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Addsimps [Compl_Times_UNIV1, Compl_Times_UNIV2]; 
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(*** The abstract type of programs ***)
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val rep_ss = simpset() addsimps 
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                [Init_def, Acts_def, mk_program_def, Program_def, Rep_Program, 
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		 Rep_Program_inverse, Abs_Program_inverse];
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Goal "Id : Acts F";
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by (cut_inst_tac [("x", "F")] Rep_Program 1);
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by (auto_tac (claset(), rep_ss));
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qed "Id_in_Acts";
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AddIffs [Id_in_Acts];
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Goal "insert Id (Acts F) = Acts F";
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by (simp_tac (simpset() addsimps [insert_absorb, Id_in_Acts]) 1);
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qed "insert_Id_Acts";
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AddIffs [insert_Id_Acts];
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(** Inspectors for type "program" **)
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Goal "Init (mk_program (init,acts)) = init";
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by (auto_tac (claset(), rep_ss));
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qed "Init_eq";
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Goal "Acts (mk_program (init,acts)) = insert Id acts";
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by (auto_tac (claset(), rep_ss));
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qed "Acts_eq";
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Addsimps [Acts_eq, Init_eq];
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(** The notation of equality for type "program" **)
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Goal "[| Init F = Init G; Acts F = Acts G |] ==> F = G";
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by (subgoals_tac ["EX x. Rep_Program F = x",
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		  "EX x. Rep_Program G = x"] 1);
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by (REPEAT (Blast_tac 2));
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by (Clarify_tac 1);
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by (auto_tac (claset(), rep_ss));
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by (REPEAT (dres_inst_tac [("f", "Abs_Program")] arg_cong 1));
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by (asm_full_simp_tac rep_ss 1);
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qed "program_equalityI";
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val [major,minor] =
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Goal "[| F = G; [| Init F = Init G; Acts F = Acts G |] ==> P |] ==> P";
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by (rtac minor 1);
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by (auto_tac (claset(), simpset() addsimps [major]));
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qed "program_equalityE";
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(*** These rules allow "lazy" definition expansion 
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     They avoid expanding the full program, which is a large expression
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***)
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Goal "F == mk_program (init,acts) ==> Init F = init";
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by Auto_tac;
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qed "def_prg_Init";
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(*The program is not expanded, but its Init and Acts are*)
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val [rew] = goal thy
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    "[| F == mk_program (init,acts) |] \
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\    ==> Init F = init & Acts F = insert Id acts";
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by (rewtac rew);
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by Auto_tac;
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qed "def_prg_simps";
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(*An action is expanded only if a pair of states is being tested against it*)
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Goal "[| act == {(s,s'). P s s'} |] ==> ((s,s') : act) = P s s'";
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by Auto_tac;
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qed "def_act_simp";
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fun simp_of_act def = def RS def_act_simp;
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(*A set is expanded only if an element is being tested against it*)
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Goal "A == B ==> (x : A) = (x : B)";
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by Auto_tac;
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qed "def_set_simp";
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fun simp_of_set def = def RS def_set_simp;
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(*** co ***)
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(*These operators are not overloaded, but their operands are sets, and 
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  ultimately there's a risk of reaching equality, which IS overloaded*)
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overload_1st_set "UNITY.constrains";
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overload_1st_set "UNITY.stable";
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overload_1st_set "UNITY.unless";
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val prems = Goalw [constrains_def]
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    "(!!act s s'. [| act: Acts F;  (s,s') : act;  s: A |] ==> s': A') \
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\    ==> F : A co A'";
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by (blast_tac (claset() addIs prems) 1);
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qed "constrainsI";
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Goalw [constrains_def]
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    "[| F : A co A'; act: Acts F;  (s,s'): act;  s: A |] ==> s': A'";
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by (Blast_tac 1);
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qed "constrainsD";
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Goalw [constrains_def] "F : {} co B";
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by (Blast_tac 1);
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qed "constrains_empty";
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Goalw [constrains_def] "F : A co UNIV";
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by (Blast_tac 1);
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qed "constrains_UNIV";
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AddIffs [constrains_empty, constrains_UNIV];
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(*monotonic in 2nd argument*)
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Goalw [constrains_def]
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    "[| F : A co A'; A'<=B' |] ==> F : A co B'";
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by (Blast_tac 1);
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qed "constrains_weaken_R";
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(*anti-monotonic in 1st argument*)
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Goalw [constrains_def]
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    "[| F : A co A'; B<=A |] ==> F : B co A'";
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by (Blast_tac 1);
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qed "constrains_weaken_L";
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Goalw [constrains_def]
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   "[| F : A co A'; B<=A; A'<=B' |] ==> F : B co B'";
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by (Blast_tac 1);
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qed "constrains_weaken";
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(** Union **)
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Goalw [constrains_def]
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    "[| F : A co A'; F : B co B' |] ==> F : (A Un B) co (A' Un B')";
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by (Blast_tac 1);
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qed "constrains_Un";
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Goalw [constrains_def]
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    "ALL i:I. F : (A i) co (A' i) ==> F : (UN i:I. A i) co (UN i:I. A' i)";
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by (Blast_tac 1);
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qed "ball_constrains_UN";
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(** Intersection **)
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Goalw [constrains_def]
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    "[| F : A co A'; F : B co B' |] ==> F : (A Int B) co (A' Int B')";
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by (Blast_tac 1);
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qed "constrains_Int";
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Goalw [constrains_def]
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    "ALL i:I. F : (A i) co (A' i) ==> F : (INT i:I. A i) co (INT i:I. A' i)";
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by (Blast_tac 1);
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qed "ball_constrains_INT";
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Goalw [constrains_def] "F : A co A' ==> A <= A'";
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by Auto_tac;
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qed "constrains_imp_subset";
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(*The reasoning is by subsets since "co" refers to single actions
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  only.  So this rule isn't that useful.*)
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Goalw [constrains_def]
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    "[| F : A co B; F : B co C |] ==> F : A co C";
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by (Blast_tac 1);
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qed "constrains_trans";
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Goalw [constrains_def]
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   "[| F : A co (A' Un B); F : B co B' |] ==> F : A co (A' Un B')";
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by (Clarify_tac 1);
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by (Blast_tac 1);
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qed "constrains_cancel";
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(*** stable ***)
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Goalw [stable_def] "F : A co A ==> F : stable A";
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by (assume_tac 1);
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qed "stableI";
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Goalw [stable_def] "F : stable A ==> F : A co A";
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by (assume_tac 1);
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qed "stableD";
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(** Union **)
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Goalw [stable_def]
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    "[| F : stable A; F : stable A' |] ==> F : stable (A Un A')";
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by (blast_tac (claset() addIs [constrains_Un]) 1);
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qed "stable_Un";
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Goalw [stable_def]
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    "ALL i:I. F : stable (A i) ==> F : stable (UN i:I. A i)";
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by (blast_tac (claset() addIs [ball_constrains_UN]) 1);
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qed "ball_stable_UN";
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(** Intersection **)
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Goalw [stable_def]
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    "[| F : stable A; F : stable A' |] ==> F : stable (A Int A')";
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by (blast_tac (claset() addIs [constrains_Int]) 1);
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qed "stable_Int";
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Goalw [stable_def]
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    "ALL i:I. F : stable (A i) ==> F : stable (INT i:I. A i)";
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by (blast_tac (claset() addIs [ball_constrains_INT]) 1);
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qed "ball_stable_INT";
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Goalw [stable_def, constrains_def]
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    "[| F : stable C; F : A co (C Un A') |] ==> F : (C Un A) co (C Un A')";
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by (Blast_tac 1);
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qed "stable_constrains_Un";
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Goalw [stable_def, constrains_def]
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  "[| F : stable C; F :  (C Int A) co  A' |] ==> F : (C Int A) co (C Int A')";
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by (Blast_tac 1);
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qed "stable_constrains_Int";
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(*[| F : stable C; F :  co (C Int A) A |] ==> F : stable (C Int A)*)
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bind_thm ("stable_constrains_stable", stable_constrains_Int RS stableI);
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(*** invariant ***)
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Goal "[| Init F<=A;  F: stable A |] ==> F : invariant A";
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by (asm_simp_tac (simpset() addsimps [invariant_def]) 1);
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qed "invariantI";
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(*Could also say "invariant A Int invariant B <= invariant (A Int B)"*)
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Goal "[| F : invariant A;  F : invariant B |] ==> F : invariant (A Int B)";
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by (auto_tac (claset(), simpset() addsimps [invariant_def, stable_Int]));
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qed "invariant_Int";
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(*** increasing ***)
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Goalw [increasing_def, stable_def, constrains_def]
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     "mono g ==> increasing f <= increasing (g o f)";
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by Auto_tac;
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by (blast_tac (claset() addIs [monoD, order_trans]) 1);
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qed "mono_increasing_o";
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Goalw [increasing_def]
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     "increasing f <= {F. ALL z::nat. F: stable {s. z < f s}}";
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by (simp_tac (simpset() addsimps [Suc_le_eq RS sym]) 1);
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by (Blast_tac 1);
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qed "increasing_stable_less";
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(** The Elimination Theorem.  The "free" m has become universally quantified!
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    Should the premise be !!m instead of ALL m ?  Would make it harder to use
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    in forward proof. **)
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Goalw [constrains_def]
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    "[| ALL m:M. F : {s. s x = m} co (B m) |] \
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\    ==> F : {s. s x : M} co (UN m:M. B m)";
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by (Blast_tac 1);
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qed "elimination";
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(*As above, but for the trivial case of a one-variable state, in which the
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  state is identified with its one variable.*)
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Goalw [constrains_def]
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    "(ALL m:M. F : {m} co (B m)) ==> F : M co (UN m:M. B m)";
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by (Blast_tac 1);
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qed "elimination_sing";
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(*** Theoretical Results from Section 6 ***)
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Goalw [constrains_def, strongest_rhs_def]
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    "F : A co (strongest_rhs F A )";
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by (Blast_tac 1);
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qed "constrains_strongest_rhs";
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Goalw [constrains_def, strongest_rhs_def]
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    "F : A co B ==> strongest_rhs F A <= B";
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by (Blast_tac 1);
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qed "strongest_rhs_is_strongest";